Manually variable pitch propeller



Dec. 2, 1969 A. v. SORRENTINO MANUALLY VARIABLE PITCH PROPELLER 5 Sheets-She 1 Filed Dec. 13, 1967 [far/@2250? ZIZZZQ y Vficwwemf'z'rzy J2 7faw/ammgl v 552 o".

1386- 1969 A. v. 'SORRENTINO MANUALLY VARIABLE PITCH PROPELLER 3 Sheets-Shem- 2 Filed Dec. 13, 1967 fizz/eniaw Sayre/2256220 6 W EJZ W m m in a n y Z2 Q WW 4 z fl H Dec. 2, 1969 A. v. SORRENTINO MANUALLY VARIABLE PITCH PROPELLER 3 Sheets-Shee 5 Filed Dec. 13, 1967 m w ,9 Z n5 1 w United States Patent 3,482,261 MANUALLY VARIABLE PITCH PROPELLER Anthony V. Sorrentino, Flossmoor, Ill. (289 Brentwood Drive, Palatine, Ill. 60067) Filed Dec. 13, 1967, Ser. No. 690,187 Int. Cl. B63h 3/02 U.S. Cl. 416-137 9 Claims ABSTRACT OF THE DISCLOSURE A variable pitch propeller assembly including a collar axially shiftable along the propeller shaft for camming arms carried by the blades to a preselected pitch. Compression springs between the blade hub and the collar absorb the reactive thrust of the indexing movement and cause a return of the blades to a preselected position when the collar is moved away from the hub.

The present invention is directed to new and useful improvements in mechanism for changing the pitch of propeller blades which may be of the type used for boats and ships.

Variable pitch propellers have been known for a number of years and some variable pitch mechanisms, particularly in aircraft propellers, has become a relatively expensive proposition. The need for simple, inexpensive and rugged mechanism which enables a change in pitch of the propeller blades on relatively inexpensive propeller systems is readily apparent. Accordingly, the primary purposes of the present invention are to so form a variable pitch propeller structure in such a manner that it may be easily applied to existing propeller systems; as for example in outboard motors, to so arrange and design variable pitch mechanism of this type that it is relatively rugged, durable and inexpensive, and to so arrange mechanism of this type that the pitch of the propeller blades may easily be changed through manually actuated means, power assisted means, and with or without some automatic means for changing pitch in response to torque and speed requirements of the engine and blades.

These and other purposes of the invention will become more apparent in the course of the ensuing specification and claims when taken with the accompanying drawings, in which:

FIGURE 1 is a side view of variable pitch propeller blade mechanism incorporating the principles of the present invention;

FIGURE 2 is a sectional view of the system illustrated in FIGURE 1 and illustrating pitch changing mechanism;

FIGURE 3 is a sectional view of the invention taken on the section lines 33 of FIGURE 2;

FIGURE 4 is a perspective view of a typical boat propeller assembly incorporating the principles of the present invention;

FIGURE 5 is a sectional illustration of a modified form of the invention and incorporating the principles of the invention;

FIGURE 6 is a sectional view taken on the section line 6-6 of FIGURE 5; and

FIGURE 7 is a side view of a variant form of actuating linkage which may be used with the present invention.

With specific reference now to the drawings and in the first instance to FIGURE 1, the numeral 10 designates a propeller drive shaft. A hub 11 is fixed to the drive shaft in the usual manner as by means of a bolt 12 and washer 13. Hub 11 has symmetrically spaced bores 14 formed therein for purposes of rotatably mounting propeller blade shafts 15 therein. The propeller blades are designated at 16. Each propeller blade includes a boss or enlargement 17 which may bear against the exterior of the hub. Washers may be positioned between the bosses and the hub. The hub may include counterbores 18 or recesses in which are seated nuts 19 which are threaded on the inner ends of the blade shafts so as to hold the blades on the hub while the blades are mounted for rotation about an axis extending transversely of the axis of the drive shaft. The hub may be keyed to drive shaft 10 in the usual manner as illustrated by the keys 20.

As is seen particularly in FIGURE 2, an indexing collar 21 is mounted on shaft 10 for rotation with shaft 10 while being slidable axially of shaft 10. Compression springs 22 are spaced symmetrically about axis of shaft 10 and extend between hub 11 and the collar 21. The springs 22 are seated within recesses 23 and 24 formed in the opposed faces of the collar and hub respectively. Guide pins 25 extend through the springs and into recesses in both the collar and hub. The pins may be fixed to collar 23 as by the keys 25a and slidably received in bores 26 which are formed in hub 11 and which extend generally parallel to the axis of shaft 10. The pins 25 are required to keep the springs in position and guide the springs during movements toward and away from hub 11.

Each of the blades includes an indexing cam arm 27 which extends laterally from each of the blades. As formed, the arms 27 are formed integrally with the bosses 17, although they may be separately affixed. Each arm 27 extends generally from one side of the axis of the blade and in a direction generally parallel with the axis of the drive shaft 10. The outer ends of the arms 27 are formed with a slight curvature and are seated within circumferentially spaced recesses 28 which are formed in the periphery of indexing collar 21. The surfaces defining these recesses are generally curvilinear in form as designated at 29 and 30 to provide cam surfaces engageable with the opposite surfaces of arms 27. The surfaces 29 and 30 are spaced so that at some positions of collar 21, the arms 27 are in contact with one surface while being out of contact with the other. The spacing is necessary to provide the camming motion.

The blades 16 are designed so that the center of pressure on the blades, when the blades are rotating in a.

fluid, is offset from the center C of the blades and generally as designated at the point P in FIGURE 1. This produces a turning moment on the blades which tends to rotate the blades and arms 27 in a counterclockwise direction as seen in FIGURE 1 so that the arms 27 bear snugly against the surfaces 30 and are held thereagainst during rotation of the blades, thus reducing any tendency of the actuating arms 27 to flutter back and forth between the surfaces 29 and 30 during rotation of the propeller blades.

A disc 31 of low friction material such as Teflon, plastic or the like is positioned around shaft 10 and bears against the face of collar 21 most remote from the propeller blades. A pressure transmitting block 32 is mounted around drive shaft 10 and bears against the disc 31. In order to shift pressure transmitting block or plate 32 axially of shaft 10, a lever 33 is pivotally mounted as at 34 on a boat frame member or other stationary element 35. Lever 33 includes a yoke portion 36 which straddles drive shaft 10 and which engages pins 37 held by plate or block 32. An actuating link 38 is connected to lever 33 and may lead to any suitable location of control. For example, on a boat it may lead to a location alongside the steering wheel of the boat. The link 38 may, if desired, be tied in mechanically with the throttle operating linkage of the motor which drives drive shaft 10 so that the pitch of blade 16 is automatically changed with changes in the operating speed of the motor. On the other hand, the linkage 38 may be operated manually and independently of the throttle linkage.

In operation, shifting of link 38 rotates lever 33 about axis 34. For example, motion of link 38 to the left in FIGURE 1 will cause shifting of pressure transmitting plate or block 32 to the right and cam surface 29 will engage arms 27 on blade 16 to rotate the blades. Shifting of the collar 21 to the dotted line position in FIGURE 1 will cause corresponding movement of the propeller blades to the dotted line position illustrated in FIGURE 1. The shifting of the collar 21 compresses springs 22 and the blade reaction forces developed in the springs 22 hold the camming surfaces 29 snug against the actuating arms 27. Conversely, movement of the link 38 to the right in FIGURE 1 will withdraw pressure plate or block 32 to the left and the springs 28 will force collar 21 to the left to force the propeller blades to return to the minimum or reducer pitch illustrated by full line position. The particular pitch may be selected at any point between the two general extremes illustrated in FIGURE 1. When the blades are rotating in the water, the reaction forces on the blades rotate the blades to a position where arms 27 are in contact with the surfaces 3!).

FIGURES 4, and 6 and 7 illustrate modifications which may be utilized with the invention. In these figures the propeller blade mounting assembly and indexing arms 27 are the same as in FIGURES 1-3. The collar 40 in these figures cooperates with the indexing arms 27 in the same manner as that specified with respect to FIG- URES 1-3, and the reaction springs 22 are mounted between the blade hub and the collar 40 in the same manner described with respect to FIGURES 13. In FIGURES 4, 5 and 6 a protective shroud, which is in the form of a cylindrical sleeve 41, is fixed to the collar 40, as by screws 42, and overlies the space between the collar 40 and hub 11. The shroud 41 may include recesses 43 which are generally aligned with the blades so that when the shroud has shifted to the right in FIGURE 5, the shroud will not interfere with the blades. The recesses are sized and proportioned to allow the walls of the recesses to fit around the propeller blades.

In FIGURES 4, 5 and 6, axial movement is transmitted to collar 40 by means of a block 44 and a pressure transmitting disc 44a of low friction material such as Teflon or the like. Holding blocks or guides 45 are seated in circumferentially spaced recesses 46 in the block 44. The guides 45 are carried by a sleeve 47. Sleeve 47 has a camming groove 47a therein, and a projection 47!), carried by a part of the motor support 48, engages in this groove. The block 44 has a plurality of spaced recesses therein as at 49 to accommodate the ends of indexing arms 27 when block 44 is shifted to the right from the position illustrated in FIGURE 5. A link 50 is connected to the sleeve 47 by a universal joint or a loose pivot as at 50a as to produce rotation of sleeve 47 upon reciprocating movement of the link 50.

The stationary element 48 may be formed as a part of the blade support 50b.

In FIGURES 4, 5 and 6, reciprocation of link 50 rotates sleeve 47 which is then shifted axially towards and away from the propeller hub due to the camming engagement between projection 47b and groove 47a. Axial movement of the sleeve 47 to the right in FIG- URE 5 transmits pressure through guides 45 to the block 44 and to the low friction disc 44a to move the indexing collar 40 to produce indexing of the propeller blades 16.

FIGURE 7 illustrates a variant form of linkage for transmitting axial movement from the pressure plate to the indexing arms 27. In FIGURE 7, for example, a support 51 may extend downwardly and outwardly from a portion of a boat 52. The element 52 may also be taken as generally representative of the type of support illustrated at 5011 in FIGURE 4. Support 51 has a bell crank 53 pivotally mounted thereon as a 4. One arm 4 of the bell crank is pivotally connected as at 55 to an actuating link 56. The other arm 57 of thebell crank has a slot 58. The walls of this elongated slot engage a pin or projection 59 on the pressure plate so that, upon reciprocation of link 56, the crank is rotated to transmit axial pressure to the projection 59 and thus shift the pressure plate toward and away from the propeller hub.

The actuating linkages for the pressure plate may be manually operated and may be controlled by a separate hand-actuated level in the cockpit of the boat. Power mechanism may be associated with the linkage to provide power actuation of the linkages, in lieu of complete manual control of the linkage and attendant control of the pitch of the blades. The pitch may be controlled automatically so that the pitch is changed with changes in operating speed of the boat. On the other hand, torque sensing devices may be utilized to sense the torque load on the engine and automatically adjust the pitch through some power mechanism.

It should be noted that as long as the indexing collar 21 is to the left of the extreme position of movement, represented generally in dotted outline in FIGURE 1, the blades can yield upon encountering an obstruction in a counterclockwise direction by virtue of the cammiug engagement between the arms 27 and the surfaces 30 which may produce movement of the collar 21 to the right in FIGURE 1 followed by return of the collar to a bearing engagement with the pressure disc under infiuence of the springs 22.

When the mechanism is used with boats, adjustment of the pitch of the blades will enable the attainment of relatively fast boat speeds in shorter periods of time, which is a distinct advantage when towing loads.

Whereas I have shown and described an operative form of the invention, it should be understood that this showing and description thereof should be taken in an illustrative or diagrammatic sense only. There are modifications to the invention which will fall Within the scope and spirit thereof and which will be apparent to those skilled in the art. The scope of the invention should be measured only by the scope of the hereinafter appended claims.

The embodiments of this invention in which an exclusive property or privilege is claimed are defined as follows:

1. A variable pitch propeller assembly including a propeller drive shaft and a propeller mounting hub fixed for rotation on said shaft, a plurality of propeller blades mounted for rotation in said hub about axis extending generally transversely of the axis of said shaft, each propeller blade including an indexing arm fixed to its associated blade and extending laterally therefrom, said indexing arm extending in a generally parallel axial direction with respect to said propeller drive shaft, an indexing collar amounted for rotation with said shaft and for sliding movement thereon while being spaced from said hub, resilient means between said hub and said collar for biasing said collar away from said hub, said collar including cam means engageable with each of said arms for causing rotation of said propeller blades to a preselected pitch in response to axial movement of said collar on said shaft, and means for shifting said collar axially of said shaft and towards and away from said hub to thereby vary the pitch of said blades.

2. The structure of claim 1 wherein said collar includes recesses formed therein, and said recesses define camming surfaces engageable with said arms.

3. The structure of claim 1 characterized by and including a protective shroud carried by said indexing collar and surrounding said collar and hub and overlying the space therebetween.

4. The structure of claim 1 wherein said last named means includes a pressure plate mounted in surrounding relation to said shaft, said plate carrying a ring in slidable engagement with a groove extending around the axis of said shaft and on said collar.

5. The structure of claim 1 wherein said resilient means includes coiled springs extending between said hub and said collar and spaced symmetrically around the axis of said shaft, the ends of said springs being seat-ed in recesses in said collar and hub, each spring surrounding a guide pin extending between and seated within said collar and said hub.

6. The structure of claim 1 wherein said last named means includes a pressure transmitting plate mounted in surrounding relation to said shaft and having means rotatably engaged with said collar, and a bell crank linkage for shifting said pressure plate and thereby causing axial movement of said collar.

7. A variable pitch propeller assembly including a propeller drive shaft and a propeller mounting hub fixed for rotation on said shaft, a plurality of propeller blades mounted for rotation in said hub about axis extending generally transversely of the axis of said shaft, each propeller blade including an indexing arm fixed to its associated blade and extending laterally therefrom, said indexing arm extending in a generally parallel axial direction with respect to said propeller drive shaft, an indexing member mounted for rotation with said shaft and for sliding movement with respect thereto while being spaced from said hub, said indexing member including spaced camming surfaces associated with each of said arms and engageable with each associated arm for causing rotation of said propeller blades to a preselected pitch in response to axial movement of said indexing member on said shaft, means for shifting said indexing member axially of said shaft and towards and away from said hub to vary the pitch of said blades, each of said blades having a configuration such as to provide a center of pressure offset from the axis of rotation of said blades whereby fluid forces acting on said blades during rotation thereof force said arms into snug engagement with one of said surfaces.

8. The structure of claim 7 wherein said surfaces associated with each arm are spaced from one another by a distance greater than the dimensions of saidarms so that said arms, in at least some positions of said indexing member, may be in contact with one of said surfaces and out of contact with the other.

'9. A variable pitch propeller assembly including a propeller drive shaft and a propeller mounting hub fixed for rotation on said shaft, a plurality of propeller blades mounted for rotation in said hub about an axis extending generally transversely of the axis of said shaft, each propeller blade including an indexing arm fixed to its associated blade and extending laterally therefrom, an indexing member mounted for rotation with said shaft and for sliding movement with respect thereto while being spaced from said hub, said indexing member including spaced camming surfaces associated with each of said arms and engageable with each associated arm for causing rotation of said propeller blades to a preselected pitch in response to axial movement of said indexing member on said shaft, said surfaces associated with each arm being spaced from one another by a distance greater than the dimensions of said arms so that said arms, in at least some positions of said indexing member, may be in contact with one of said surfaces and out of contact with the other, means of shifting said indexing member axially of said shaft and towards and away from said hub to vary the pitch of said blades, resilient means including coiled springs extending between said hub and said indexing member and being spaced symmetrically around the axis of said shaft, the ends of said springs being seated in recesses in said indexing member and hub, each spring surrounding a guide pin extending between and seated Within said indexing member and said hub, each of said blades having a configuration such as to provide a center of pressure offset from the axis of rotation of said blades whereby fluid forces acting on said blades during rotation thereof force said arms into snug engagement with one of said surfaces.

References Cited UNITED STATES PATENTS 457,513 8/1891 Littlejohn 170-16053 X 1,582,166 4/1926 Cederquist 170-16047 2,080,540 5/1937 Isaac 170160.46 2,099,922 11/ 1937 Bellman 170160.51 3,216,507 11/1965 Curioni 170160.51 X 3,273,656 9/1966 Bird 170160.51 X 2,455,251 11/1948 Hersey.

FOREIGN PATENTS 434,604 9/1935 Great Britain.

456,407 9/1936 Great Britain.

449,664 7/ 1936 Great Britain.

325,662 4/ 1935 Italy.

' EVERETTE A. POWELL, JR., Primary Examiner US. Cl. X.R. 416167 

